In a graphG= (V; E), a subset S Í V (G) is said to be an open packing setof G if no two vertices of S have a common neighbour inG: The maximum cardinality of an open packing set is called the open packing numberof G and is denoted by ro (G). This parameter has been studied in [5], [6], [7] and [8]. In this paper, we characterize the graphs G with ro (G) =n - 2, ro (G) =n -w (G) and ro (G) =n - D (G), where n, w (G) and D (G) denote the order, clique number and the maximum degree of G. Also, we discuss the open packing number for split graphs.

Background: During the last decade, increased rates of drug traffic have led the smugglers to use various methods. One of these methods of illicit drug smuggling is body packing. Smuggling by intra-abdominal concealment is called "body packing". In this research, mortality rate was investigated due to body packing in Tehran.Methods: A descriptive study (case series) was designed on all corpses referred to the Forensic Medicine Organization of Tehran between April 1999 - December 2000. Demographic data such as sex, age, marital status, addiction, job, education level, type of opioid and the weight, number of packets, and results of blood and urine morphine tests by thin-layer chromatographic method were investigated. Results: Continental system of law is used in Iran and 0.06% of the referred corpses to Forensic Medicine Organization of Tehran were body packers. There were 12 cases, all of them were men. The mean age of body packers was 43 years (range 20 – 62). The minimum weight of the packets was 20 g and the maximum weight was 1400 g (mean = 501 g). The minimum number of the packets was one and the maximum number of the packets was 48. Twenty five percent of the corps were putrefied and one corpse was mummified. None of the body packers had academic education nor were employed. Nine of them lived in cities. Twenty five percent of them were intravenous addicts. The corpses were found mostly in terminals (17%), roads (58%), and cities (25%). Conclusion: Hospital physicians may neglect this type of gastrointestinal foreign body if they are not aware of the body packer syndrome. Body packing should be suspected in anyone with signs of drug-induced toxic effects after a recent arrival on city terminals or when there is no history of recreational drug use.

The main issues in nasal surgery are to stabilize the nose in the good position after surgery and preserve the cartilages and bones in the favorable situation and reduce the risk of deviation recurrence. Also it is necessary to avoid the synechia formation, nasal valve narrowing, hematoma and bleeding. Due to the above mentioned problems and in order to solve and minimize them nasal packing, nasal splint and nasal mold have been advised. Patients for whom the nasal packing used may faced to some problems like nasopulmonary reflex, intractable pain, sleep disorder, post operation infection and very dangerous complication like toxic shock syndrome. We have two groups of patients and three surgeons (one of the surgeons used post operative nasal packing in his patients and the two others surgeons did not).Complications and morbidities were compared in these two groups. Comparing the two groups showed that the rate of complication and morbidities between these two groups were same and the differences were not valuable, except the pain and discomfort post operatively and at the time of its removal. Nasal packing has several risks for the patients while its effects are not studied. Septoplasty can be safely performed without postoperative nasal packing. Nasal packing had no main findings that compensated its usage. Septal suture is one of the procedures that can be used as alternative method to nasal packing. Therefore the nasal packing after septoplasty should be reserved for the patients with increased risk of bleeding.

Many communities in the world use groundwater as a source of potable water. The high nitrate concentration is a serious problem in groundwater usage. This study utilizes a biological denitrification method to investigate a moving bed biofilm reactor (MBBR) for the case of Tehran's groundwater. One pilot-scale MBBR with a 3 liter volume was designed and used in this research. The denitrification reactor operates under anoxic conditions. Methanol was used as a carbon source in the reactor throughout the study, and fifty percent of the reactor volume was occupied with KMT packing (k1). To determine the optimum nitrate loading rate, the concentration of nitrate changed from 100 to 400 mg N/l. It was concluded that heterotrophic denitrifying bacteria converted nitrate to nitrogen. According to obtained results, the removal efficiency and optimum loading rate were estimated during the experiments in different concentrations and different HRTs for this type of reactor. Sodium nitrate was in the feed source in the anoxic reactor. The maximum removal rate of nitrate was measured to be 2. 8 g of NO3N m-2-1 carrier d. Therefore, it was shown that the optimum loading rate of nitrate and the optimum COD/N were equal to 3. 2 g of NO3-N m-2 -1 carrier d and 6 g of COD/g N respectively.